Help with content of /etc/network/interfaces file

Nils Kassube kassube at
Sun Feb 21 23:02:07 UTC 2010

Jay Ridgley wrote:
> When I enter an ifconfig it shows the three nics, however, eth2 does
>  not have an IP address. If I remove the comment flag(#) from the
>  iface line and the auto line my network fails to come up. Any
>  examples I have found seem to avoid this type of arrangement (two
>  nics doing DHCP one a client (for the internet) and one a server
>  (for the Access Point).

If I understand it correctly, you have eth0 connected to the internet 
and you get your configuration via DHCP from your provider. On your eth1 
you have a first LAN where your DHCP server should hand out 
configuration to other machines and on eth2 you have a second LAN via 
that AP where your DHCP server should also hand out configuration data 
to other machines.

Now, if you uncomment the eth2 entries, there are two interfaces with 
DHCP entries (eth0 + eth2). These entries mean that the ports should act 
as DHCP clients. I suppose that's why your network fails to come up.

> interfaces:
> iface eth0 inet dhcp
> auto eth0
> iface eth1 inet static
> address
> netmask
> gateway
> broadcast

Are you sure that the gateway should be the same as the interface 
itself? That doesn't look right to me. IMHO the gateway should be the 
address of the internet port, i.e. the address received for eth0.

> dhcpd.conf:

> #DHCP subnet a wireless Access Point for eth2
> subnet netmask {
>      range;
>          option routers; is not in this subnet - I don't think this entry can work.


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